Each time new seasonally adjusted estimates become available, trend estimates are revised. This revision is a combined result of the concurrent seasonal adjustment process and the application of surrogates of the Henderson average to the seasonally adjusted series (see paragraphs 28 to 36 of the Explanatory Notes).

The examples in the tables below show two illustrative scenarios and the consequent revisions to previous trend estimates of employment and the unemployment rate. The revisions in the scenarios are due to the use of surrogates of the Henderson average, as the impact of revision of seasonally adjusted estimates can not be estimated in advance.

1 The October seasonally adjusted estimate is higher than the September estimate by:
0.24% for employment
2.10% for the unemployment rate

2 The October seasonally adjusted estimate is lower than the September estimate by:
0.24% for employment
2.10% for the unemployment rate

The percentage changes of 0.24% and 2.10% represent the average absolute monthly percentage changes in employment and the unemployment rate respectively. Estimates in the graphs have been calculated using unrounded estimates, and may be different from, but more accurate than, rounded estimates depicted in its corresponding table.